1. Field of the Invention
This invention relates to methods and apparatus for electronically diagnosing and analyzing the performance of machines, such as internal combustion engines. The invention relates particularly to digital engine analyzers of the type which display digitized information on an oscilloscope screen.
2. Description of the Prior Art
The present invention is an improvement of the digital engine analyzer disclosed in U.S. Pat. No. 5,250,935, the disclosure of which is incorporated herein by reference. That analyzer includes a set of probes for coupling to an associated automotive engine under analysis and for receiving input signals therefrom. The analyzer processes these signals, digitizes them and stores them for further processing and/or display. The system also is responsive to the input signals for generating display data for display on a CRT display screen.
The system disclosed in U.S. Pat. No. 5,250,935 is sold by Snap-on Incorporated under the designation MT-3000. That system is available with a remote control unit, much like a television remote control, by which an operator can operate the front panel controls of the engine analyzer from a remote location up to 20 feet away. However, this requires that the operator be in the line of sight to the analyzer display screen so that he can see the screen and must be close enough so that he can discern what is being displayed, so as to determine which control functions need to be exercised and to be able to confirm their execution.
It is known to transmit display data from a central processing unit to a remote display unit by wire transmission over telephone lines, such a system being disclosed, for example, in U.S. Pat. No. 4,739,253. However, such wire-line systems are not suitable for use in automotive service or repair facility environments. It is also known to utilize portable computer terminals in wire or wireless communication with other terminals in a network system, but such portable terminals operate substantially like any other computer terminal, having substantial processing power, and being quite expensive.